Accumulated Other Comprehensive Loss (Reclassification) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Mar. 31, 2014		Mar. 31, 2013		Mar. 31, 2014		Mar. 31, 2013
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Other (income) expense, net	$ (17.0)		$ (18.0)		$ (37.4)		$ (29.6)
Interest expense	31.5		35.2		64.8		71.0
Net Income Attributable to Air Products	(283.5)		(290.4)		(573.7)		(568.7)
Net income attributable to noncontrolling interests	8.0		9.2		16.9		18.1
Reclassification Out Of Accumulated Other Comprehensive Income [Member] | (Gain) Loss on Cash Flow Hedges [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Sales/cost of sales	0.8		0		1.0		0.7
Other (income) expense, net	(11.1)		7.0		(23.0)		(8.0)
Interest expense	(0.5)		(0.4)		(0.7)		(0.4)
Net Income Attributable to Air Products	(10.8)		6.6		(22.7)		(7.7)
Reclassification Out Of Accumulated Other Comprehensive Income [Member] | Pension and postretirement benefits [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net Income Attributable to Air Products	$ 20.6	[1]	$ 24.2	[1]	$ 40.6	[1]	$ 48.6	[1]

[1] The components include prior service cost amortization, actuarial loss amortization, and settlements and are reflected in net periodic benefit cost. Refer to Note 9, Retirement Benefits.